Want a straight answer The design is the same as you use on a Z-1/KZ. The problem is some stock 650 buckets were heat treated incorrectly and broke. The shims are changed to different thicknesses to get correct clearance but are the correct ones.The stock retainers are usually replace with aftermarket aluminum or titanium for a weight savings/performance gain. Nothing like a straight anwser.

As far as my experience goes, the stock stuff is as good if not better than the aftermarket. The only exception is the weight of the stock vs. the titainium retainers, and the stock ones are probably stronger. Also check the installed spring height. If I remember correctly, it is slightly different but nothing that can't be adjusted.

Thanks Bill, thats what I think also. Stock stuff is generally better then aftermarket pieces in most cases. If the buckets lasted 10,000 or 30,000 ,miles in a street bike why wouldnt they last in a dragbike The weight does concern me a bit with life of the rest of the valve train, how much more do these weight then SOB

The stock 650 bucket is similar to aftermarket. I have personally seen stock 650 buckets break,it makes a real mess out of the head. In the amount of years gone by the bad ones have probably already broken. Get a good set of springs.